Numerous studies have examined the short-term efficacy of psychostimulant medication and behavior modification (the two evidence-based treatments) in the treatment of ADHD, but insufficiencies in acute effects of both treatments have been noted, leading to the widespread use of the combination of the two approaches. However, the combined approach to treatment has not yet been extensively studied in either short- or long-term evaluations. Numerous critical issues regarding ADHD treatment remain unresolved. A primary unresolved issue is how the intensity or dose of behavioral and pharmacological treatments and their combination influence the results of comparative efficacy studies. One of the major supporting arguments that proponents of combined treatments have made is that combining treatments enables the use of lower doses of medication and less intensive behavioral treatment relative to unimodal treatments; however, this concept has not been empirically studied in a well-controlled trial. The purpose of the proposed study is to examine the relative effects of and interactions between different doses of behavioral (none, low, and high) and pharmacological treatments (pl, .3mg/kg, and .6mg/kg) for ADHD by evaluating their separate and combined effects in a controlled summer program setting. The following specific aims are addressed: 1) Do combined treatments have incremental efficacy beyond their components, and does the answer to this question vary with the dose/intensity of the behavioral treatment and the dose of medication; 2) Do the answers to question 1 depend on domain of functioning (e.g., peer relationships, academic functioning, disruptive behavior, interactions with adults); 3) Do the answers to question I depend on the setting in which effects are assessed (i.e., recreational settings with peers, classroom settings, home/family settings); 4) How do individual difference variables (i.e., age. gender, severity of impairment, comorbid child diagnoses, family and parent characteristics) influence the answers to questions addressed above and; 5) What are the impacts of different intensities of behavioral, pharmacological, and combined treatments on parent, teacher, and counselor affect, stress, effort, and satisfaction with treatment? These questions will be answered in a within-subject investigation with 144 ADHD children between the ages of 5 and 12 in which each child receives all conditions. We will employ a variety of ecologically valid measures of functioning in a summer treatment program setting that has been well studied with respect to both behavioral and pharmacological treatments and allows precise of treatment fidelity and objective outcomes. Treatment effects will be analyzed at both the group and child level.